ARM: correctly align constant pool value on Thumb1 targets.

Since we're using tLDRpci to access it, the constant pool's address must be 0
(mod 4).

llvm-svn: 249163
diff --git a/llvm/lib/Target/ARM/ARMFrameLowering.cpp b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
index 5b5b1b0..476a12f 100644
--- a/llvm/lib/Target/ARM/ARMFrameLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
@@ -1968,7 +1968,7 @@
     ARMConstantPoolValue *NewCPV = ARMConstantPoolSymbol::Create(
         MF.getFunction()->getContext(), "__STACK_LIMIT", PCLabelId, 0);
     MachineConstantPool *MCP = MF.getConstantPool();
-    unsigned CPI = MCP->getConstantPoolIndex(NewCPV, MF.getAlignment());
+    unsigned CPI = MCP->getConstantPoolIndex(NewCPV, 4);
 
     // ldr SR0, [pc, offset(STACK_LIMIT)]
     AddDefaultPred(BuildMI(GetMBB, DL, TII.get(ARM::tLDRpci), ScratchReg0)